Vacuum tube construction



June 4, 1940. E. K. SMITH.

VA'CUUM TUBE CONSTRUCTION Filed Aug. 26, 1939 2 Sheets-Sheet 1 QIEIQI'EFiTOR 2 BY 2 r I ATTORNEY June 4, 1940. E. K. SMITH VACUUM TUBE CONSTRUCTION Filed Aug. 26, 19:59 v 2 Sheets-Sheet 2 I g Ens. o v a! 5 9 I n w Ill l| III w\\\\\. I V

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ATTORNEY VACUUM TUBE CONSTRUCTION Earl K. Smith, West Orange, N. 1., assignor to Electrons, Inc., a corporation of Delaware Application August 26, 1939, Serial No. 292,007

This invention relates to rectifiers and has for 4 Claims.

its object to provide a simple, compact and sturdy full-wave rectifier construction. capable of withstanding heavy mechanical shocks, and 6 especially adapted to withstand high voltages when the rectifieris of the gas filled type.

The invention willbe described withreference to, the accompanying drawings, in which Fig. 1 is a side view; Fig. 2 is a sectional side view (perpendicular to the view in Fig. 1), omitting the base;

Fig. 3 is a horizontal section taken at line 3-3 of Fig. 2;

Fig. 4 is another horizontal section taken at line l-l of Fig. ,2;

Fig. 5 is a further horizontal section taken at line 5-5 of Fig. 2;

Fig. 6 is a perspective view of the exterior shield and its support; Fig. '7 shows in perspective the component parts of the interior. shield;

Fig. 8 shows in perspective the upper and lower anodes; and l r Fig. 9is a diagram showing conventional connections of the tube to the source of power.

An envelope I of suitable construction and shape, preferably glass with a reentrant portion 2,.is mounted on a suitable base 3 in usual manner. The electrodes and shields within the tube are all axially concentric and supported by supports or conductors mounted upon or extending through the bottom of the tube or the reentrant portion thereof. For example, in the construction shown, the two anodes I and 5, respectively,

are cylindrical in shape, and each is provided with a bridge piece 6, and], respectively, to which is attached a conductor 9 and 8, respectively, extending through the envelope l and supporting the respective anodes.

An outer metallic cylindrical heat shield I0, so

proportioned that the outer periphery of the cylinder almost meets the inner wall of the envelope l, is supported by supports ll, l2, attached to and supported by a clamp l3 clamped to the reentrant portion 2. A circular metallic disc I4 is fitted to the inside of theouter heat shield i0 midway between the anodes, and divides the tube into two chambers and separates the anodes. A hole 15 in the disc permits the conductor support 9 to pass through. The hole and conductor are both surrounded by the tube l6 extending from the disc M, to which it is securelyfastened, to the reentrant. portion 2. Glass tubes l1 and I8, respectively, may extend upward from the reentrant portion.

the disc II are interior heat shields l9 and 20,

is exposed to the respective anodes by openings side of the circuit by the supporting conductor across the disc between the two anodes. To pre- Mounted upon the upper and lower surfaces of respectively, both metallic, cylindrical in shape, and axially concentric with the anodes and outer heat shield, being attached to the disc ll by 5 suitablelegs 2|, 22, respectively, spaced apart to provide openings between the lower end of the upper heat shield l9 and the disc II. t

A cathode 23 common to the two anodes is located within the inner heat shields i9, 20, and 10 24 in the respective shields. From one side of the cathode circuit a conductor 25 leads to a cross piece 26 on the supports for the outer heat shield l0, and thereby the entire heat shield 15 system, outer, inner and disc, is electrically connected to the cathode. The upper shield carries a conductive bridge 21 to which is connected the circuit including the coils 23, 23, or other emissive portion of the cathodes for the respective anodes. The cathode 23 is connected to the other 29. Where the cathode conductor passes through the disc II a small conduit 30 of insulating and refractory material fits snugly between the con- 25 ductor and the disc. The maximum permissible size of the clearance opening between the cathode and sleeve 30 and between the sleeve and disc I 4 will be governed by the concentration of the ionization and by the anode voltage used, smaller openings being necessary for higher voltages and greater concentrations. The same size limitation applies to any other openings in the disc, between disc and outer heat shield ID, or throughout the length of tube It.

The cathode may be of any suitable type such as tungsten or oxide coated, or preferably of the type in which one of the oxygen compounds of a metal of the iron group and a metal of the alkaline earth group, such as barium nickelate is dissolved in a nickel core.

The terminals 25, 29, 9 and 8 are connected to the source of power in any well known manner. One such is shown in Fig. 9 in which the generator 3| supplies a transformer 32, one secondary 45 coil 33 supplying current to heat the cathode 23, and another coil 34 supplying the current to be rectified between the cathode and the respective anodes.

In operation the electron discharge to each anode occurs only from the cathode portion which is on the same side of the partitioning disc ll, passing through the holes in the corresponding shield I9 or 20, and no discharge occurs vent any substantial leakage discharge past the disc at high voltage, the disc extends substantially imperforate almost to the wall of the vessel. The shielding tube It around anode lead 9 prevents leakage to this lead from anode i. This reduction of leakage current permits higher volt-,

ages to be used on the anodes than otherwise.

The concentric arrangement of the cylindrical electrodes and shields about the centrally located cathode provides a compact arrangement of the electrodes in which there is little danger of injury from mechanical shocks and which is capable of operating at high voltages with little leakage. The rigidly supported shielding system common to both halves of the rectifier in the same tube, in addition to providing complete separation of the two halves, provides a rigid supporting platform for the top of the filament and also for the cathode shields l9 and 2'. Since the filament and shields are relatively immune to shock and bending and the anodes are light and adequately supported by their individual supports 8 and 9, there is little opportunity for either anode to contact with the shield.

I claim:

1. A full-wave rectifier comprising an envelope, a cathode having two axiallyaligned emitting surfaces, two axially aligned and axially concentric anodes, one surrounding and opposite to each emitting portion of the cathode and concentric therewith; and. a shielding system consisting of an inner and an outer cylinder concentric with the anodes, each cylinder shielding both anodes and being divided by a diaphragm separating the opposite anodes from each other and each anode from the cathode except its own opposite emitting surface, the entire shielding system being electrically connected to both cathode emitting surfaces.

2. A full-wave rectifier comprising a gas-filled vessel, a centrally located cathode, a pair of cylindrical anodes coaxially aligned and located one above the other concentrically around said cathode, a cylindrical shield open for electron passage located concentrically between the cathode and anodes, a cylindrical shield concentrically around the anodes, a rigidly supported and substantially imperforate disc extending substantially across said vessel between said anodes, said shields and cathode being supported on and electrically connected to said disc.

3. A full-wave gas-filled rectifier comprising a cathode havingtwo axially aligned emitting surfaces; two axially aligned and axially concentric anodes, one surrounding and opposite to each emitting portion of the cathode and concentric therewith; a shielding a comprising a metallic disc intermediate e two anodes and the cathode emitting surfaces and perpendicular to the axis thereof, and inner and outer metallic cylindrical shields mounted on and electrically connected with said disc and axially aligned with the cathodes and anodes, the inner shield being interposed between the cathode emitting surfaces and the anode and having openings to permit electron passage from the respective cathode emitting surfaces to the corresponding anode and the outer shield being interposed between the anodes and the envelope; and longitudinal supports for the several elements.

4. A full-wave rectifier comprising a gas-filled Vessel, a substantially imperforate metal disc rigidly supported from the base of said tube and having an outer metallic cylindrical shield around its periphery and electrically connected therewith; a perforated cylindrical inner shield fastened to and electricallyconnected with each side of said disc; and a cathode passing through and insulated from said disc within the inner cylindrical shield and having an emitting portion on each side of the disc, the said emitting portions being in electrical series with each other and with the shielding system; and apair of coaxially aligned cylindrical anodes, one on each side of said disc, concentrically surrounding the respective inner shields and surrounded by said outer shield.

EARL K. SMITH. 

